TTP/C-C1 Communications Controller Data Sheet

AS8201

Rev. NC, October 1999

Page 3 of 13

Austria Mikro Systeme International AG

The CNI (controller network interface) forms a temporal firewall. It decouples the controller

network from the host subsystem by use of a dual ported RAM. This prevents the propagation

of control errors. The interface to the host CPU is implemented as 16 bit wide non-multiplexed

asynchronous bus interface.

TTP/C follows a conflict-free media access strategy called time-division-multiple access

(TDMA). This means, TTP/C deploys a time slot technique based on a global time which is

permanently synchronised. Each node is assigned a time slot in which it is allowed to perform

transmit operation. The sequence of time slots is called TDMA round, a set of TDMA rounds

forms a cluster cycle. After one cluster cycle the operation of the network repeats. The

sequence of interactions forming the cluster cycle is defined in a static time schedule, called

message-descriptor-list (MEDL). The definition of the MEDL in conjunction with the global time

determines the response time for a service request.

The membership of all nodes in the network is evaluated by the communication controller. This

information is presented in a consistent fashion to all correct cluster members. During

operation, the status of every other node is propagated within one TDMA round. The MEDL is

loaded into the configuration memory before run time when the system starts up.

Package and Pin Assignmen t

Type: PQFP 120, plastic quad flat package

TTP/C-C1

Communications

Controller

(TOP VIEW)

Figure 1 PQFP 120 pin package and pin assignment